WASHINGTON - Convenience stores will have to start stocking a variety of "staple foods" alongside the snacks and fountain drinks if they want to keep accepting food stamps, under a little-noticed section of the farm bill.

The provision, tucked into the nearly 1,000-page bill signed into law Friday by President Barack Obama, would require that stores increase the "depth of stock" in four of those staples: bread or cereals, vegetables or fruits, dairy products, and meat, poultry or fish.

Convenience store chain officials said recently that they think they can meet the new standards. And nutritionists said they think it could lead to better food options for low-income shoppers.

But both said it will depend on the details of the regulations and how they are implemented.

"It sounds OK, but I don't know," said Kelly Jackson, a registered dietitian and professor at the University of Arizona's Department of Nutritional Sciences.

She sees potential hurdles for convenience stores that typically stock items that are "higher in fat, sodium, salt and sugar." She said one challenge could be convenience stores that are not equipped for the turnover rate of fresh produce, which may make increasing stock difficult.

"When you have candy in the checkout aisle instead of fruits and vegetables ... that's another challenge in a place like that," Jackson said.

Lyle Beckwith of the National Association of Convenience Stores said most members of the group's board of directors have told him they will carry more items if it is necessary to comply with the Supplemental Nutrition Assistance Program - SNAP, or food stamps.

"It will really come down to the individual store, whether they benefit from SNAP or not," said Beckwith, the association's senior vice president of government relations.

He said some stores may choose to increase their stock regardless of the amount of food stamps they accept, while others may see the costs outweigh the benefits.

Under the changes to the Food and Nutrition Act of 2008, convenience stores that accept food stamps will now have to have at least seven items in each category of staple foods, up from three items per category that were required before. The changes also would require a perishable food item in at least three of the categories, up from two categories previously.

Beckwith could not provide hard numbers but believes that of the 2,220 convenience stores in Arizona, "a significant number accept and receive SNAP" benefits.

All 590 Circle K convenience stores in Arizona accept food stamps, and that is not expected to change under the new law, said Terry Brown, a Phoenix-based brand and marketing manager for the chain.

"Being able to accept SNAP is a privilege that we want to maintain," Brown said in an email. "So, we will do what we can to take care of our SNAP customers."

Mike Thornbrugh, the manager of public and governmental affairs for QuikTrip, said he thinks most of the company's convenience stores will be able to meet the new threshold. The chain has 104 stores in Arizona, primarily in the Phoenix and Tucson areas.

"We should be in pretty good shape, and, if not, we should be able to react fairly quickly" to meet the new requirements, Thornbrugh said.

Kristi L. King, a spokeswoman for the Academy of Nutrition and Dietetics, said that overall she was "happy with the increase in variety for SNAP participants."

"However, I hope that in the future requirements are made so that the stocking requirements meet the Dietary Guidelines for Americans," she said.

King, who is a registered dietitian nutritionist, said education will be "essential" for both retailers and SNAP recipients.

"I have seen healthy options at the convenience stores, but consumers must remember that convenience stores are meant to supplement needs, not to be a full grocery store," King said. "One should not rely solely on convenience stores to do a majority of their shopping with their SNAP funds."

But in Arizona, reliance on convenience stores for groceries is higher than in other states because a high percentage of the state's population lives in "food deserts" - a low-income area with low access to grocery stores.

About 20 percent of Arizonans lived in food deserts in 2010, according to a U.S. Department of Agriculture Economic Research Service definition that counts people who live more than a half-mile from a grocery in urban areas and more than 10 miles in rural areas. That was about 5 percentage points more than the national average.

Only Louisiana, Texas and New Mexico had higher rates of people living in food deserts, based on the most recent USDA data, which compared 2010 Census numbers with a comprehensive list of supermarkets, supercenters and large grocery stores from that year.